The absence of a father has adverse physical and behavioral consequences for a growing child, especially boys, reveals a recent study.

Researchers from Princeton University reported that the loss of a father has an adverse effect on telomeres, the protective nucleoprotein end caps of chromosomes. At nine years of age, children who had lost their fathers had significantly shorter telomeres - 14 percent shorter on average - than children who had not.

Telomeres are thought to reflect cell aging and overall health; their role is to help maintain the DNA ends of chromosomes following cell division. Each time a cell divides, its telomeres shorten; once telomeres are too short, cell replication stops. Previous research has suggested that shortened telomeres are associated with a wide range of diseases in adults, including cardiovascular disease and cancer.

Researchers analysed 5,000 children born in large U.S. cities at the turn of the 21st century. Information was gathered on the children’s physical and mental health, cognitive function, social-emotional skills, schooling and living conditions, as well as the makeup, stability and financial resources of their families.

They then examined whether the way they got separated from their father - incarceration, death, separation or divorce - and the timing of the loss, whether in early childhood or middle childhood mattered and to what extent. They determined that the loss of a father is clearly associated with cellular function as estimated by telomere length: if a child loses their father between the period of birth and 9 years, it leads to a reduction in telomere length. The effect is the greatest at 16 % for those children whose fathers die.

Corresponding author Daniel Notterman said that if the father is being removed from the life of a child then that is plausibly associated with an increase in stress, for both economic and emotional reasons. This association is especially strong for boys who lost or were separated from their fathers before the age of five. A child’s genotype may lessen the association between a child’s social environment and telomere length, and serve as a protective factor. The research is published in the journal Pediatrics.